1. Technical Field
The invention relates to Policy Based System Management especially for distributed computer systems. The invention further relates to conflict resolution in computer systems.
2. Related Art
Distributed systems are a well known phenomenon for large organisations. Such systems consist of a large number of heterogeneous components and the systems and their components provide significant management burdens for system administrators. Various solutions for management of distributed systems such as Open View (Hewlett Packard) and TeMIP (Compaq) are available but these require significant manual intervention. As a result as the complexity of the system increases, management capability is further stretched. Most current solutions are centralised and suffer significantly from heterogeneity problems arising from the use in different distributed systems of different types of communication protocols and methods.
Recently attention has been given to system management based on policies, for example the Internet Engineering Taskforce (IETF) policy framework which specifies general requirements for policy based management and applies it to management of internet routers with the intent of making the configuration more straightforward. The open view solution identified above as well as secure policy managers (Cisco Systems) and Policy Based Network Management (PBNM-Intel) all contain implementations based on the IETF policy framework. The existing solutions, however, assume a single point of control with a centralised policy repository and decision making. The known solutions further focus on specific applications such as network quality of service.
Although the use of policies to specify the behaviour of the system is expected to have wider applicability than individual items of network equipment, extending also to software processes running on this equipment, the existing centralised management approach is not a scaleable solution.
FIG. 1 shows a distributed system designated generally 10 including a variety of sub networks 12, 14, 16 each having a range of components 12a, 12b, 14a, 14b, 14c, 16a. The system is controlled from a central point of control 18 which includes a centralised policy manager 20. The problem with this type of system is that it is unlikely that all the policy-controlled elements will themselves be capable of interpreting policies and evaluating appropriate behaviour in response to changing circumstances. The range of components requiring management may be far greater than that considered in most policy based management work.
The particular problem with such systems is the relative inflexibility of the system. Significant front-end manual intervention is often required when further components are added to the system both in updating policies relevant to the additional component and in rewriting existing policies to avoid any conflict problems.